There is always interest in investigating new lactic acid bacteria strains for product development that can complement or replace currently-in-use starters. This study screened native strains of Streptococcus thermophilus from various plant/dairy sources across India and compared them with commercial yoghurt starters. A total of 158 isolates were characterised as S. thermophilus by polyphasic approach and strain typed using (GTG)₅ primers by repetitive sequence-based polymerase chain reaction. After cluster analysis, 12 major clusters were defined at a similarity level of 70%. They were evaluated for functionally important metabolic traits and representative genotypes with desired starter activity were used for yoghurt production along with commercial starter. Based on physico-chemical attributes, sensory and principal component analysis, yoghurt prepared using representative plant and dairy isolates were indistinguishable from product prepared using reference yoghurt strains. The identified strains were promising with additional functional attributes such as galactose fermenting ability and negative for urease activity.

人们总是有兴趣研究用于产品开发的新乳酸菌菌株，这些菌株可以补充或替代当前使用的发酵剂。这项研究筛选了来自印度各地不同植物/乳制品的天然嗜热链球菌菌株，并将它们与商业酸奶发酵剂进行了比较。共有 158 个分离株通过多相方法和使用 (GTG) _{5 分型的}菌株被鉴定为嗜热链球菌通过基于重复序列的聚合酶链反应引物。聚类分析后，定义了 12 个主要聚类，相似度为 70%。对它们的功能上重要的代谢性状进行评估，并将具有所需发酵剂活性的代表性基因型与商业发酵剂一起用于酸奶生产。根据理化属性、感官和主成分分析，使用代表性植物和乳品分离物制备的酸奶与使用参考酸奶菌株制备的产品没有区别。鉴定出的菌株具有额外的功能属性，例如半乳糖发酵能力和脲酶活性阴性。